
<h1><span class="yiyi-st" id="yiyi-13">numpy.ma.is_mask</span></h1>
        <blockquote>
        <p>原文：<a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.ma.is_mask.html">https://docs.scipy.org/doc/numpy/reference/generated/numpy.ma.is_mask.html</a></p>
        <p>译者：<a href="https://github.com/wizardforcel">飞龙</a> <a href="http://usyiyi.cn/">UsyiyiCN</a></p>
        <p>校对：（虚位以待）</p>
        </blockquote>
    
<dl class="function">
<dt id="numpy.ma.is_mask"><span class="yiyi-st" id="yiyi-14"> <code class="descclassname">numpy.ma.</code><code class="descname">is_mask</code><span class="sig-paren">(</span><em>m</em><span class="sig-paren">)</span><a class="reference external" href="http://github.com/numpy/numpy/blob/v1.11.3/numpy/ma/core.py#L1458-L1523"><span class="viewcode-link">[source]</span></a></span></dt>
<dd><p><span class="yiyi-st" id="yiyi-15">如果m是有效的标准掩码，则返回True。</span></p>
<p><span class="yiyi-st" id="yiyi-16">此函数不检查输入的内容，只有类型为MaskType。</span><span class="yiyi-st" id="yiyi-17">特别地，如果掩码具有灵活的dtype，此函数返回False。</span></p>
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<tr class="field-odd field"><th class="field-name"><span class="yiyi-st" id="yiyi-18">参数：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-19"><strong>m</strong>：array_like</span></p>
<blockquote>
<div><p><span class="yiyi-st" id="yiyi-20">数组进行测试。</span></p>
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<tr class="field-even field"><th class="field-name"><span class="yiyi-st" id="yiyi-21">返回：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-22"><strong>result</strong>：bool</span></p>
<blockquote class="last">
<div><p><span class="yiyi-st" id="yiyi-23">如果<em class="xref py py-obj">m.dtype.type</em>是MaskType，则为True，否则为False。</span></p>
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<div class="admonition seealso">
<p class="first admonition-title"><span class="yiyi-st" id="yiyi-24">也可以看看</span></p>
<dl class="last docutils">
<dt><span class="yiyi-st" id="yiyi-25"><code class="xref py py-obj docutils literal"><span class="pre">isMaskedArray</span></code></span></dt>
<dd><span class="yiyi-st" id="yiyi-26">测试输入是否为MaskedArray的实例。</span></dd>
</dl>
</div>
<p class="rubric"><span class="yiyi-st" id="yiyi-27">例子</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="kn">import</span> <span class="nn">numpy.ma</span> <span class="k">as</span> <span class="nn">ma</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">m</span> <span class="o">=</span> <span class="n">ma</span><span class="o">.</span><span class="n">masked_equal</span><span class="p">([</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">],</span> <span class="mi">0</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">m</span>
<span class="go">masked_array(data = [-- 1 -- 2 3],</span>
<span class="go">      mask = [ True False  True False False],</span>
<span class="go">      fill_value=999999)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ma</span><span class="o">.</span><span class="n">is_mask</span><span class="p">(</span><span class="n">m</span><span class="p">)</span>
<span class="go">False</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ma</span><span class="o">.</span><span class="n">is_mask</span><span class="p">(</span><span class="n">m</span><span class="o">.</span><span class="n">mask</span><span class="p">)</span>
<span class="go">True</span>
</pre></div>
</div>
<p><span class="yiyi-st" id="yiyi-28">输入必须是一个ndarray（或具有相似的属性），它被认为是一个有效的掩码。</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">m</span> <span class="o">=</span> <span class="p">[</span><span class="kc">False</span><span class="p">,</span> <span class="kc">True</span><span class="p">,</span> <span class="kc">False</span><span class="p">]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ma</span><span class="o">.</span><span class="n">is_mask</span><span class="p">(</span><span class="n">m</span><span class="p">)</span>
<span class="go">False</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">m</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="kc">False</span><span class="p">,</span> <span class="kc">True</span><span class="p">,</span> <span class="kc">False</span><span class="p">])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">m</span>
<span class="go">array([False,  True, False], dtype=bool)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ma</span><span class="o">.</span><span class="n">is_mask</span><span class="p">(</span><span class="n">m</span><span class="p">)</span>
<span class="go">True</span>
</pre></div>
</div>
<p><span class="yiyi-st" id="yiyi-29">具有复杂dtypes的数组不返回True。</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">dtype</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">dtype</span><span class="p">({</span><span class="s1">&apos;names&apos;</span><span class="p">:[</span><span class="s1">&apos;monty&apos;</span><span class="p">,</span> <span class="s1">&apos;pithon&apos;</span><span class="p">],</span>
<span class="go">                      &apos;formats&apos;:[np.bool, np.bool]})</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">dtype</span>
<span class="go">dtype([(&apos;monty&apos;, &apos;|b1&apos;), (&apos;pithon&apos;, &apos;|b1&apos;)])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">m</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([(</span><span class="kc">True</span><span class="p">,</span> <span class="kc">False</span><span class="p">),</span> <span class="p">(</span><span class="kc">False</span><span class="p">,</span> <span class="kc">True</span><span class="p">),</span> <span class="p">(</span><span class="kc">True</span><span class="p">,</span> <span class="kc">False</span><span class="p">)],</span>
<span class="go">                 dtype=dtype)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">m</span>
<span class="go">array([(True, False), (False, True), (True, False)],</span>
<span class="go">      dtype=[(&apos;monty&apos;, &apos;|b1&apos;), (&apos;pithon&apos;, &apos;|b1&apos;)])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ma</span><span class="o">.</span><span class="n">is_mask</span><span class="p">(</span><span class="n">m</span><span class="p">)</span>
<span class="go">False</span>
</pre></div>
</div>
</dd></dl>
